Method to make PMR head with integrated side shield (ISS)

ABSTRACT

A PMR head comprises a substrate, a magnetic pole formed over the substrate, the pole having a pole tip having a cross-sectional tapered shape wherein the pole tip is surrounded by a write gap layer, an integrated shield comprising side shields on the substrate laterally surrounding the pole tip and a trailing shield overlying the pole tip and integral with the side shields.

RELATED PATENT APPLICATION

U.S. patent application Ser. No. 11/906,717 filed on Oct. 3, 2007 andassigned to the same assignee of the present invention, and hereinincorporated by reference in its entirety.

BACKGROUND OF THE INVENTION

(1) Field of the Invention

This invention is related to magnetic recording heads and, moreparticularly, to shielding of perpendicular magnetic recording heads.

(2) Description of the Related Art

In order to push for high track density perpendicular magnetic recording(PMR), it is necessary to have side shield PMR design to reduce fringeand to improve side erasure. There are several proposals to usesubtractive methods such as reactive ion etching (RIE) or ion beametching (IBE) to etch into the magnetic shield followed by atomic layerdeposition (ALD), plating, and chemical mechanical polishing (CMP)methods to form side shield PMR. However, all these proposals do nothave a self-aligned structure between the side shield and the trailingshield.

U.S. Pat. No. 7,002,775 to Hsu et al discloses side and trailingshields, but provides no details about how they are made. U.S. Pat. No.7,253,991 to Fontana, Jr. et al teaches side and trailing shields formedby CMP, but they are not self-aligned. U.S. Pat. No. 7,068,453 to Terrisal el and U.S. Patent Application 2007/0253107 to Mochizuli et al teachthat side and trailing shields may be a single piece or they may beseparate pieces. U.S. Pat. No. 7,070,698 to Le shows side shields andtrailing shields formed separately. Co-pending U.S. Patent Application2007/0177301 to Han et al, filed on Feb. 2, 2006, discloses a method offorming side shields where the pole tip is aligned to the side shieldsand then forming an upper shield over the side shields.

U.S. Patent Applications 2007/0186408 to Nix et al and 2006/0044682 toLe et al teach self-aligned wrap-around side and trailing shields.However, the main pole in these inventions is formed by deposition andetching processes.

In co-pending patent application Ser. No. 11/906,717 (HT07-016) filed onOct. 3, 2007, a method is proposed to make a self-aligned full sideshield PMR. FIG. 1 shows the air-bearing surface (ABS) view of thisself-aligned full side shield PMR head. Main pole 16 is surrounded bywrite gap 24. Self-aligned full side shield 26 surrounds the pole.Trailing shield 28 overlies the side shield. However, using two separateprocesses to fabricate the side shield and the trailing shield createsinterface flux choking at the interface between the side and trailingshields. Adjacent track erasure (ATE) problems were observed due to thisflux choking.

SUMMARY OF THE INVENTION

It is the primary objective of the present invention to fabricate bothside shields and trailing shield of a PMR head in one fabricationprocess.

In accordance with the objective of the invention, a PMR head comprisesa substrate, a magnetic pole formed over the substrate, the pole havinga pole tip having a cross-sectional tapered shape wherein the pole tipis surrounded by a write gap layer, an integrated shield comprising sideshields on the substrate laterally surrounding the pole tip and atrailing shield overlying the pole tip and integral with the sideshields.

Also in accordance with the objective of the invention, there isdisclosed a method of fabricating a PMR head. An alumina layer isdeposited on a substrate and a trench is formed through the aluminalayer to the substrate. A first seed layer is deposited over the aluminalayer and within the trench. A magnetic main pole is formed on the seedlayer wherein the magnetic main pole comprises a main pole area and apole tip area. The first seed layer not underlying the magnetic mainpole is removed. The alumina layer is removed to create a cavity aroundthe pole tip area of the magnetic main pole. A second seed layer isdeposited over the substrate within the cavity. An integrated sideshield is formed on the second seed layer and overlying the pole tiparea.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional representation of a self-aligned full sideshield of co-pending patent application Ser. No. 11/906,717.

FIG. 2 is a cross-sectional representation of the self-alignedintegrated side shields of the present invention.

FIGS. 3-8 are cross-sectional representations of the process of thepresent invention.

FIG. 9A is a side view and FIG. 9B is a top view of a step in theprocess of the present invention.

FIG. 10A is a cross-sectional view and FIG. 10B is a top view of a stepin the process of the present invention.

FIG. 11A is a cross-sectional view and FIG. 11B is a side view of a stepin the process of the present invention.

FIGS. 12 and 13 are top views of steps in the process of the presentinvention.

FIG. 14A is a cross-sectional view and FIG. 14B is a top view of a stepin the process of the present invention.

FIG. 15 is a top view of a step in the process of the present invention.

FIG. 16A is a cross-sectional view and FIG. 16B is a top view of a stepin the process of the present invention.

FIG. 17A is a cross-sectional view and FIG. 17B is a side view of a stepin the process of the present invention.

FIG. 18 is a side view of the completed PMR head of the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides a method for fabricating self-alignedintegrated side and trailing shields for a PMR head. This methodfabricates the integrated shields in one process so as to preventinterface flux choking. FIG. 2 shows the completed self-alignedintegrated side shield of the invention. Main pole 16 is shownsurrounded by write gap 23. Integrated side and trailing shield 30 isfully aligned to the main pole.

The fabrication process of the present invention will be described withreference to the drawing figures. Referring now to FIG. 3, an ABS viewshows the first steps in a process sequence of the present invention. Aseparation layer 12 made of a dielectric material such as alumina isprovided on a substrate 10. Substrate 10 may be an etch stoppermaterial, for example. The alumina layer 12 is formed to a thickness ofbetween approximately 2000 and 4000 Angstroms by a process of physicalvapor deposition (PVD), for example. Referring now to FIG. 4, a trench13 is etched through the alumina layer 12 to the substrate 10. Now, aseed layer 14 is deposited conformally over the alumina layer 12 andinto the trench 13 using atomic layer deposition (ALD) to form a uniformside gap, as shown in FIG. 5. The seed layer is preferably Ru, formed toa thickness of between about 300 and 500 Angstroms. The layer 14 alsoacts as a CMP stopper.

Referring now to FIG. 6, the magnetic main pole 16 is electroplated ontothe seed layer 14 in the trench area. The magnetic pole layer ispreferably a layer of low coercivity magnetic material such as NiFe,CoNiFe, FeCoNi, or FeNi, for example, and it is plated to a thicknesssufficient to fill the trench in a void-free manner, typically about 0.5to 1 micron in thickness.

Then, a CMP process is performed to planarize the main pole material 16to the main pole and Ru interface, as shown in FIG. 7. Next, the Rulayer not underlying the main pole material is removed, for example,using IBE. FIG. 8 shows the ABS view after etching away of the Ru layer.FIG. 9A shows a side view of the center line and FIG. 9B shows a topview of the main pole piece at this step in the fabrication process.FIG. 8 shows the view B-B′ of the top view in FIG. 9B. FIG. 9A shows theview A-A′ of the top view in FIG. 9B.

FIG. 10A shows the ABS view and FIG. 10B shows the top view of the nextstep in the process, where the view B-B′ of FIG. 10B is shown in FIG.10A. A photoresist mask, not shown, is formed over the alumina layer 12and the main pole region. The alumina 12 is removed using, for example,IBE followed by an alkaline solution treatment, where it is not coveredby the mask, not shown, to create a cavity 19 around the selected mainpole tip area, as shown in FIGS. 10A and 10B.

Next, as shown in the ABS view in FIG. 11A and in side view in FIG. 11B,a second Ru layer 20 is deposited, preferably by ALD, over the substrate10 in the cavity areas around the main pole and over the main pole 16,as shown. The sidewall areas of the main pole, as shown in FIG. 11A,comprise the first Ru layer 12 and the second Ru layer 20 thereover. Thesecond Ru layer 20 acts as a partial side shield gap and write gap. Thetotal write gap layer has a preferred thickness of between about 300 and500 Angstroms.

Referring now to FIG. 12, a via opening for the top yoke is made throughthe Ru layer 20 to expose the main pole 16. This is preferably performedby IBE, and followed by a magnetic seed layer deposition 17 such asCoNiFe or NiFe, as shown in FIG. 13. Now, a writer shield photo patternis made using a negative resist process. Mask 22 is shown in top view inFIG. 13.

FIG. 14A shows the ABS view and FIG. 14B shows the top view of the nextstep in the fabrication process. Shield material 30 is plated on the Rulayer 20. The Ru layer 20 acts as a seed layer for the purpose of theplating process. The shield material is a layer of magnetic materialsuch as FeNi, CoNiFe, FeCoNi, or NiFe and it is plated to a thickness ofapproximately 2 microns. This plating process also forms the top yoke36, shown in FIG. 14B.

The plating seed layer 20 not covered by the shield material 30 isremoved by IBE, as shown in top view in FIG. 15.

Referring now to FIGS. 16A and 16B, the structure is covered withalumina 32 deposited by a high rate ALD or PVD process.

Now, a CMP process is performed to form the trailing portion of theintegrated shield to the target thickness of about 0.6 micron, as shownin the ABS view in FIG. 17A and in side view in FIG. 17B.

Finally, the PMR writer is completed, as known in the art. For example,side view FIG. 18 shows spirally wound electrically conducting coilsformed about the magnetic pole 16. Insulator 54, read shields 56, andwrite shield 58 are also shown.

The present invention provides an integrated side shield PMR headstructure, as illustrated in FIG. 2. There is no interface between theside shield and the trailing shield since it is formed in one processstep. The integrated side shield 30 surrounds and overlies the main poletip 16. Write gap layer 23 comprises first and second Ru layers 14 and20, respectively. The magnetic main pole has a preferred width ofbetween about 50 and 500 nm.

The integrated side shield PMR head structure of the present inventioncomprises a tapered main pole or tapered write gap with side shielddesign to reduce side fringe for further enhancement of tracks per inch(TPI), a better track profile, and elimination of adjacent track erasure(ATE) caused by flux choking at the side shield and trailing shieldinterface.

Although the preferred embodiment of the present invention has beenillustrated, and that form has been described in detail, it will bereadily understood by those skilled in the art that variousmodifications may be made therein without departing from the spirit ofthe invention or from the scope of the appended claims.

1. A PMR head comprising: a substrate; a magnetic pole formed over saidsubstrate, said pole having a pole tip having a cross-sectional taperedshape, said pole tip surrounded by a write gap layer; and an integratedshield comprising side shields on said substrate laterally surroundingsaid pole tip and a trailing shield overlying said pole tip and integralwith said side shields.
 2. The PMR head according to claim 1 furthercomprising spirally wound electrically conducting coils formed aboutsaid magnetic pole and capable of producing a magnetic field directedsubstantially perpendicularly to an ABS plane from said pole tip whensaid coils are electrically energized.
 3. The PMR head according toclaim 1 wherein said integrated shield is formed of NiFe to a thicknessbetween approximately 3000 and 4000 Angstroms.
 4. The PMR head accordingto claim 1 wherein said magnetic pole is formed of FeNi, CoNiFe, FeCo,or NiFe to a thickness of approximately 2 microns.
 5. The PMR headaccording to claim 1 wherein said write gap layer is formed of Ru to athickness between approximately 300 and 500 Angstroms.
 6. The PMR headaccording to claim 1 wherein said magnetic pole has a width betweenapproximately 50 and 500 nm.
 7. A method of fabricating a PMR headcomprising: providing a substrate; depositing a separation layer on saidsubstrate and forming a trench through said separation layer to saidsubstrate; depositing a first seed layer over said separation layer andwithin said trench; forming a magnetic main pole on said first seedlayer wherein said magnetic main pole comprises a main pole area and apole tip area; removing said first seed layer not underlying saidmagnetic main pole; removing said separation layer to create a cavityaround said pole tip area of said magnetic main pole; depositing asecond seed layer over said substrate within said cavity; and forming anintegrated side shield on said second seed layer and overlying said poletip area.
 8. The method according to claim 7 wherein said depositingsaid separation layer comprises depositing alumina by physical vapordeposition to a thickness between approximately 2000 and 4000 Angstroms.9. The method according to claim 7 wherein said trench is inwardlytapered.
 10. The method according to claim 7 wherein said depositingsaid first seed layer comprises atomic layer deposition of Ru to athickness of between about 300 and 800 Angstroms.
 11. The methodaccording to claim 7 wherein said forming said magnetic main polecomprises: electroplating a magnetic pole layer onto said first seedlayer; and planarizing said magnetic pole layer to said first seed layerwherein said first seed layer acts as a stopper for said planarizingprocess.
 12. The method according to claim 7 wherein said magnetic mainpole comprises NiFe, CoNiFe, FeCoNi, or FeNi having a thickness ofbetween approximately 0.5 to 1 micron.
 13. The method according to claim7 wherein said removing said first seed layer comprising etching awaysaid first seed layer to said separation layer.
 14. The method accordingto claim 7 wherein said removing said separation layer to create acavity around said pole tip area of said magnetic main pole comprises:forming a photoresist mask over said separation layer and said main polearea; removing said separation layer not covered by said mask to exposeunderlying said substrate to create said cavity around said pole tiparea wherein said removing said separation layer comprises reactive ionetching and wet etching using an alkaline solution; and removing saidphotoresist mask.
 15. The method according to claim 7 wherein saiddepositing said second seed layer comprises depositing a Ru layer byatomic layer deposition.
 16. The method according to claim 7 whereinsaid first and second seed layers comprise Ru and form a partial sideshield gap and a write gap wherein a total write gap thickness isbetween approximately 300 and 500 Angstroms.
 17. The method according toclaim 7 wherein said forming said integrated side shield comprises:electroplating shield material on said second seed layer; removing saidsecond seed layer not covered by said shield material, depositing analumina layer over said shield material by atomic layer deposition orphysical vapor deposition; and planarizing said shield material to athickness of approximately 0.6 micron over said pole tip area.
 18. Themethod according to claim 17 wherein said shield material comprisesFeNi, CoNiFe, FeCoNi, or NiFe and has a thickness of approximately 2microns.
 19. The method according to claim 17 further comprising:opening a via to said main pole area through said second seed layer; andforming a writer shield mask pattern using a negative resist processwherein said electroplating said shield material also forms a top yokewithin said via.
 20. The method according to claim 7 further comprisingforming an electrically conducting coil about said magnetic main pole,said coil, when energized, capable of producing a magnetic field fromsaid pole tip that is directed substantially perpendicular to an ABSplane.